Clinico-pathologic correlations of myofibroblastic tumors of the oral cavity. II. Myofibroma and myofibromatosis of the oral soft tissues.

BACKGROUND: Myofibroma is a solitary benign tumor of myofibroblasts. Myofibromatosis describes multiple, simultaneous myofibromas at different sites in various organs. The clinico-pathologic correlations of myofibroma/myofibromatosis confined only to oral soft tissues were analyzed.

METHODS: In the English language literature, 41 myofibroma and 12 myofibromatosis cases involving the oral soft tissues were found. From our files, three new myofibroma cases were added.

RESULTS: Age at time of diagnosis of oral mucosa myofibroma ranged from birth to 70 years (mean 21.7 years), considerably higher than myofibroma in other parts of the body. Lesions occurred during the first decade (44%) and in the first year of life (17%). Male:female ratio was 1:1.6, contrary to the male predominance in other parts of the body. Common sites were the tongue (32%) and buccal mucosa (18%). Treatment was local excision, either complete (n = 13) or partial (n = 3), wide excision (n = 4), surgery, and chemotherapy (n = 1). Myofibromatosis involving oral soft tissues was diagnosed at birth in nine (75%) patients, within the first year in two, and as a young adult in one. Male:female ratio was 2:1. The tongue was the most common site (50%). Half the patients died of disseminated disease within a few days from birth, three were cured by partial or complete excision, and three experienced spontaneous regression. Histologically, oral mucosa myofibroma/myofibromatosis appearance agreed with findings in the literature.

CONCLUSIONS: Myofibroma should be included in the clinical differential diagnosis of masses of the oral soft tissues, especially in the tongue and buccal mucosa of children and adolescents. Histological differential diagnosis includes benign and malignant spindle-shaped lesions. Treatment of choice is local excision.